Rayleigh scattering, named after the 19th-century British physicist Lord Rayleigh, is the predominantly elastic scattering of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scattering medium, the amount of scattering is inversely proportional to the fourth power of the wavelength, e.g., a blue color is scattered much more than a red color as light propagates through air.
Rayleigh scattering causes the blue color of the daytime sky and the reddening of the Sun at sunset.
Scattered blue light is polarized. The picture on the right is shot through a polarizing filter: the polarizer transmits light that is linearly polarized in a specific direction.
Rayleigh scattering in opalescent glass: it appears blue from the side, but orange light shines through.
John William Strutt, 3rd Baron Rayleigh
John William Strutt, 3rd Baron Rayleigh, was a British mathematician and physicist who made extensive contributions to science. He spent all of his academic career at the University of Cambridge. Among many honours, he received the 1904 Nobel Prize in Physics "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies." He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919.
Rayleigh in 1904
Caricature of Lord Rayleigh in the London magazine Vanity Fair, 1899
Theory of sound, 1894